Projection filament lamp

ABSTRACT

An electric filament lamp for projection purposes in which the two straight ends of the filament body are incorporated in a pinch seal and are each surrounded by a member supporting said ends; said members are preferably constructed as helically wound wires of unequal lengths and are incorporated at their ends in the pinch seal.

United States Patent Van Beek [45] Dec. 19, 1972 s41 PROJECTION FILAMENT LAMP [56] References Cited Inventor: Ferdinandlls Maria Jouphus Van i Beek, Emmasingel, Eindhoven,

Netherlands 2,404,992 7/1946 Stone ..313/271 X 2.226381 121940 E ..313 271 [73] Assignee: U.S. Philips Corporation, New wmg I York Primary Examiner-Roy Lake {22] Filed: Feb. 9, 1971 Assistant Examiner-James B. Mullins [21] APPL No: 113,876 Attorney-Frank R. Tnfarl v [57] v 1 ABSTRACT F 11 t i [30] orelgn App ca ion Prior ty Data An electric filament lamp for projection purposes in Feb. 18, 1970 Netherlands ..7002305 which the two straight ends of the filament body-are incorporated in a pinch seal and are each surrounded U-S- ...313/222, a member supporting said ends; said members are 313/285 preferably constructed as helically wound wires of [51] Int. Cl. ..H0lk unequal lengths and are incorporated at their ends in [58] Field of Search ..3 13/219, 222, 271, 275, 276, the pinch Sea1 4 Claims, 1 Drawing Figure INVENTOR.

FERDINANDUS M.J.VAN BEEK Pmmennammz I z I I The invention relates to an electric filament lamp, in

particular a halogen projection lamp, in which the current supply conductors of the filament arranged at right angles to the longitudinal direction of the lamp are secured in a pinch seal present at one end of the lamp, each 'of the conductors being surrounded by a member which supports said conductors and is incorporated at its one end in the pinched seal and is situated at its other end in the lamp space. Such a filament lamp is known from the U.S. Pat. specification No. 3,470,410.

In the known filament lamp which is constructed as a mono-pinch halogen filament lamp, the two singlecoiled current supply conductors which are connected to a coiled-coil'filament are each surrounded by helically wound supportings spiral of equal lengths which are incorporated at their one end in the pinch seal and project in the lamp space at their other end. As a result of this, a flexible support of the conductors and a reasonable resistance of the lamps against shocks and vibrations is obtained in a direction transverse to the longitudinal direction of the lamp.

Ithas now been found that the resistance to shocks and vibrations of the known lamp is considerably improved, if according to the invention the two supporting members, which are preferably also constructed as helically wound wires, project in the lamp space over mutually unequal distances. This is probably due to the fact that in a lamp having supporting members of unequal lengths, fewer resonance deformations occur than in a lamp in which the supporting members are equally long. It has also been surprisingly found that the light are which upon fusing of a lamp is formed between two fusing conductors, is extinguished sooner when the conductors have mutually unequal lengths.

It has been found experimentally that the best results are obtained when the shorter supporting member is shown at 5.

Reference numeral 7 denotes a tungsten flattened filament'viewed against the largest face thereof. The straight ends 9' and 11 of said elements are incorporated in the pinch seal and secured to'foils 13 and 15 of molybdenum. 17 and 19 denote external conductors given a length between 20 and 90 percent of the length secured to the foils l3 and 15.

' The filament lamp shown comprises two helically wound supporting members 21' and 23 surrounding the ends 9 and 11. These supporting members are also incorporated each at one of their ends in the pinch seal,

reached, for example, when two supporting members of equal len th would be chosen.

In the em odlment shown for a 42 Volt-500 Watt lamp, the length of the member 21 is 5.5 mm and that of the member 23 is 10 mm. Both members are formed as helically wound wires of tungsten having 'a diameter of l00/um. They surround the straight ends 9 and 11, which have a diameter of 120 mm, with a clearance of approximately 0.1 mm.

What is claimed is:

' 1. An electric filament lamp, in particular a halogen projection lamp, in which the current supply conductors of the filament arranged at right angles to the longitudinal direction of the lamp are secured in a pinch seal present at one end of the lamp, each of the conductors being surrounded by a member which supports said conductors and is incorporated at its one end in the pinched seal and is located at its other end in the lamp space, wherein the members supporting the relative conductors have unequal lengths calculated from the pinch seal.

2. An electric filament lamp asclaimed in claim 1, wherein the shorter member has a length which is between 20 and percent of the length of the longer member.

3. An electric filament lamp as claimed in claim 1 or 2, wherein each member surrounds the associated current conductor with some clearance.

4. An electric filament lamp as claimed in claim 1, wherein the member is formed as a helically wound body.

5273 3 UNITED STATES PATENT OFFICE CERTIFICATE CORRECTION Patent 3705-900 ated December 19, 1972 Inventofl) 121; JOSEPHUS VAN BB Ir is certified that error appears in the above-identified patent and that; said Letters Patent are hereby corrected as shown below:

Column 2, lines 42-'43,-in "claims cancel "or 2,".

Signed and sealed this 22nd da of May 1973.

(SEAL) v Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. An electric filament lamp, in particular a halogen projection lamp, in which the current supply conductors of the filament arranged at right angles to the longitudinal direction of the lamp are secured in a pinch seal present at one end of the lamp, each of the conductors being surrounded by a member which supports said conductors and is incorporated at its one end in the pinched seal and is located at its other end in the lamp space, wherein the members supporting the relative conductors have unequal lengths calculated from the pinch seal.
 2. An electric filament lamp as claimed in claim 1, wherein the shorter member has a length which is between 20 and 90 percent of the length of the longer member.
 3. An electric filament lamp as claimed in claim 1 or 2, wherein each member surrounds the associated current conductor with some clearance.
 4. An electric filament lamp as claimed in claim 1, wherein the member is formed as a helically wound body. 